Repeated removal of blood for therapeutic and research purposes is common in hospitalized patients on clinical trials. To ensure the accuracy of these specimens, the removal of discard blood (5 to 10 ml) is standard practice. The reinfusion of this discard blood is not typically done, due to clinical concerns about clot formation. This discard or "wasting" of blood is often a concern for patients and health care providers because of the associated blood loss. The purpose of this study is to determine if discard blood from venous access devices is free from clots and suitable for reinfusion. Blood which is removed for discard prior to obtaining laboratory specimens was filtered to determine the presence of clots. Half the blood removed as discard from the vascular access device was filtered immediately upon removal from the patient to determine the presence of clot. The second half of the discard blood was allowed to dwell in a syringe for 5 minutes and then filtered to determine the presence of clots. The amount of clot present in the two samples was quantified and compared. Discard blood was not reinfused into patients in this study. A total of fifty (50) vascular access devices have been tested. Data collection has just been completed and subject accrual ended. While data analysis is underway, preliminary results suggest that clots are frequently found in initial blood discard. The clinical significance of these findings must be determined.